Thorax 1987;42:901-902 Metastatic renal cell carcinoma mimicking pleural mesothelioma D R TAYLOR, W PAGE, D HUGHES, G VARGHESE From the Departments of Medicine and Pathology, The Queen's University ofBelfast Renal cell carcinoma is renowned for its propensity to meta- lesion was found in the lungs or at the hila. Histological stasise in unusual ways. While the thorax is the most fre- examination showed vacuolated polygonal cells diagnostic quently affected site, pleural lesions are uncommon, and me- of renal cell carcinoma. Immunocytochemical studies tastasis is usually associated with parenchymal lung lesions. I confirmed the tumour to be renal in origin and excluded the We report a case in which pleural metastatic disease was the possibility of mesothelioma. Positive results on testing with sole intrathoracic abnormality and the clinical, radiological, epithelial membrane antigen, low weight cytokeratin (kidney and pathological features were identical to those of pleural associated epithelia), vimentin, and periodic acid-Schiffindi- mesothelioma. Case report A 67 year old man presented with a six week history of dry cough, increasing dyspnoea and left sided pleuritic chest pain. He had been a lifelong smoker (40 pack years) and had been exposed to asbestos 25 years earlier while working as a boiler engineer. At the age of 56 years a right sided renal cyst had been drained surgically. He denied any urinary symp- toms. Physical examination showed an obese (85 kg), afebrile man with signs of a left sided pleural effusion. A firm, non- tender mass measuring 6cm in diameter was felt in the left hypochondrium. Examination of the urine showed numer- ous pus cells but no red cells. The effusion was aspirated and pleural biopsy specimens were obtained, but cytological examination of the fluid failed to reveal malignant cells. The chest radiograph, taken after aspiration (fig 1), showed a lobulated pleural opacity extending into the paratracheal area and the presence of Fig 1 Chest radiograph taken after aspiration of the left residual fluid. Computed tomography of the thorax (fig 2) sided pleural effusion, showing the lobulated pleural opacity and abdomen showed appearances suggesting a diagnosis of extending into the paratracheal area. mesothelioma or metastatic disease; no pleural plaques were identified. Abdominal scans indicated a solid rather than cystic mass arising from the parenchyma of the left kidney. The appearances were typical of a renal cell carcinoma. Reaccumulation of pleural fluid was managed by tempo- rary insertion of an intercostal drain and tetracycline pleu- rodesis. The patient remained symptomatically stable for four months, but then deteriorated and died in respiratory failure. At necropsy the left pleural space was completely oblit- erated by white fleshy tumour, encasing the lung and pene- trating the pericardium and diaphragm. The macroscopic appearances were indistinguisable from those of pleural mesothelioma. In addition, the tumour had extended along the track of previous intercostal drainage, ending in a 4 cm lobulated subcutaneous mass. No other discreet metastatic Address for reprint requests: Dr G Varghese, Level 8, Belfast City Rommommones- n M.. All- Hospital, Belfast BT9 7AB. Fig 2 Computed tomography scan of the thorax, suggesting Accepted 23 January 1987 a diagnosis of mesothelioma or metastatic disease. 901 902 Taylor, Page, Hughes, Varghese cated a renal origin. Negative results with 52 kD cytokeratin be bilateral in their distribution, might have had an im- and MHFG2 excluded a primary mesothelioma.2 portant effect on tumour behaviour after the establishment In the right lung the pleura was grossly thickened, of a single pleural metastasis. although no plaques were seen. Asbestos fibres, mild One other feature makes this case unusual. The spread of fibrosis, and alveolar wall thickening, diagnostic of early as- tumour along the track of a previous intercostal drain in- bestosis, were widely distributed subpleurally. In the abdo- sertion is characteristic of mesothelioma and has been ob- men the presence of a large renal cell carcinoma arising from served after diagnostic thoracotomy,6 but has only rarely the left kidney was confirmed, and in the right kidney a been reported in cases of renal cell carcinoma after needle single 0 5 cm metastatic deposit was found. biopsy.7 Finally, renal cancer has been found to occur at twice the Discussion anticipated rate in a large series of asbestos exposed workers.8 Whether in our case asbestos exposure was of The thorax is the most common site for metastasis from a aetiological significance cannot be established. The case is a renal cell carcinoma, being affected in up to 55% of cases at reminder, however, that asbestos is a possible cause of some necropsy. Multiple pulmonary nodules are most frequently non-respiratory tract tumours. found, but single nodules, lymphangitis carcinomatosa, hilar and mediastinal adenopathy, endobronchial obstruction, References and thoracic wall lesions also occur. 1 3 4 Although uncommon, pleural lesions with or without I Bennington JL, Kradjian RM. Distribution of metastases from effusions are by no means rare, occurring in about 4% of renal cell carcinoma. In: Bennington JL, Kradjian RM, eds. cases. What is unusual about the present case is that the Renal carcinoma. Philadelphia: WB Saunders, 1967:156-7. clinical behaviour and pathological features of the pleural 2 Bolen JW, Hammer SP, McNutt C. Reactive and neoplastic sero- metastasis so strikingly resembled that of a primary meso- sal tissue. Am J Surg Pathol 1986;1:34-47. thelioma. We can find only one other report in which similar 3 Kutty K, Varkey B. Incidence and distribution of intrathoracic metastases from renal cell carcinoma. Arch Intern Med observations have been made.' In that case, however, paren- 1984;144:273-6. chymal lung disease was also a feature. In our patient exten- 4 Riches EW. Tumours of the kidney and ureter. In: DW Smithers, sive pleural tumour was the sole intrathoracic abnormality. ed. Neoplastic disease at various sites. Vol 5. Edinburgh: ES Although confirmed histologically to be a renal cell car- Livingstone, 1964:72-85. cinoma metastasis, the tumour in the present case had 5 Latour A, Shulman HS. Thoracic manifestations of renal cell car- spread throughout the left hemithorax in a contiguous man- cinoma. Radiology 1976;121:43-8. ner, a pattern typical of mesothelioma. Because of the his- 6 Shearin GC, Jackson D. Malignant pleural mesothelioma- report of 19 cases. J tory of asbestos exposure and the initial radiological 7 Bush WH, Burnett LL,Thoracic Cardiovasc Surg 1976;71:621-6. Gibbons RP. Needle track seeding of appearances, mesothelioma had been the clinical diagnosis; renal cell carcinoma. Am J Roentgenol 1977;129:725-7. the abdominal mass was thought to be a benign renal cyst. It 8 Selikoff IJ, Hammond EC, Seidman H. Mortality experience of is interesting to speculate that the pleural thickening and insulation workers in the United States and Canada, subpleural asbestos fibres with fibrous reaction, presumed to 1943-1976. Ann NY Acad Sci 1979;330:91-116.